Tracked live by the FAA, but its flight plan was first seen after takeoff, so we don't know the scheduled time and can't say whether it's late.

ALLEGIANT · FLIGHT G4 1399 IN THE AIR (OFF 11:45 AM ET, ETA 1:37 PM ET) · SCHEDULED TIME UNKNOWN

Wednesday, September 30 Today

G4 1399 · BOS → TYS

took off 11:45 AM ET · expected to land 1:37 PM ET (scheduled time unknown)

Forecast issued Wed 11:00 AM ET · 1h before departure

Arrive at TYS more than 15 minutes late?

19% chance · ±1 pts +8 pts · 24h

HOW SURE WE ARE Very high. The odds now come almost entirely from live conditions.

What’s moving the odds

↑ Other factors

↑ Cloud base down to 800 ft, visibility down to 2 mi forecast at BOS that day

↑ G4's recent on-time record

↓ Mostly benign weather forecast at TYS

↓ Wednesdays in September are usually quieter than average

Weather at each end

BOS (origin) Gusts8 kt Ceiling800 ft Visibility2 mi Precip0.02 in

TYS (destination) Gusts6 kt Ceilingnone (clear) Visibility10+ mi Precipnone

How this resolves

Yes if the gate arrival is more than 15 minutes after the scheduled arrival. Cancelled or diverted flights resolve N/A.

Every question here is display only — there is no betting or money involved. Gate times come from the airline; a cancellation resolves only the “Cancelled?” question, and a diversion voids the delay questions.

G4 1399 · BOS → TYS

Odds over time